1. Field of the Invention
The present invention relates to a magnetic toner for use in an image forming method such as an electrophotographic method.
2. Description of the Related Art
An electrophotographic image forming apparatus is demanded to achieve a higher speed, a longer lifetime and saving of energy, and a toner is also demanded to have still further enhanced various performances in order to respond to such demands. In particular, it is important for a longer lifetime that transfer efficiency and developability of a toner be kept even in a long period of use. In addition, a toner is demanded to have still further enhanced low temperature fixability from the viewpoints of a high speed and saving of energy.
Furthermore, an apparatus such as a copier and a printer is being downsized, and a magnetic one-component development system using a magnetic toner that is advantageous in terms of such viewpoints can be used.
Various toners have been proposed in order that a magnetic toner satisfies stable transfer efficiency and developability, and still more enhanced low temperature fixability over a long period of time. Japanese Patent Application Laid-Open No. 2006-91935 has proposed addition of an external additive having an adjusted specific resistance to a magnetic toner to result in enhancements in durability and chargeability. Japanese Patent No. 4321272 has proposed external addition of a composite resin particle of a silica particle and a melamine resin particle to a magnetic toner to result in an enhancement in developability and suppression of image deletion. Japanese Patent Application Laid-Open No. 2000-292972 has proposed external addition of silica having a large particle diameter to a magnetic toner to result in an enhancement in developability and suppression of fogging. Japanese Patent Application Laid-Open No. 2013-92748 and International Publication No. WO2013/063291 have proposed external addition of a composite particle including an inorganic fine particle embedded in the surface of a resin fine particle to result in an enhancement in durability.